1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
/*
* CPU frequency scaling for OMAP using OPP information
*
* Copyright (C) 2005 Nokia Corporation
* Written by Tony Lindgren <tony@atomide.com>
*
* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
*
* Copyright (C) 2007-2011 Texas Instruments, Inc.
* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pm_opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <asm/smp_plat.h>
#include <asm/cpu.h>
/* OPP tolerance in percentage */
#define OPP_TOLERANCE 4
static struct cpufreq_frequency_table *freq_table;
static atomic_t freq_table_users = ATOMIC_INIT(0);
static struct device *mpu_dev;
static struct regulator *mpu_reg;
static int omap_target(struct cpufreq_policy *policy, unsigned int index)
{
int r, ret;
struct dev_pm_opp *opp;
unsigned long freq, volt = 0, volt_old = 0, tol = 0;
unsigned int old_freq, new_freq;
old_freq = policy->cur;
new_freq = freq_table[index].frequency;
freq = new_freq * 1000;
ret = clk_round_rate(policy->clk, freq);
if (ret < 0) {
dev_warn(mpu_dev,
"CPUfreq: Cannot find matching frequency for %lu\n",
freq);
return ret;
}
freq = ret;
if (mpu_reg) {
rcu_read_lock();
opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
if (IS_ERR(opp)) {
rcu_read_unlock();
dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
__func__, new_freq);
return -EINVAL;
}
volt = dev_pm_opp_get_voltage(opp);
rcu_read_unlock();
tol = volt * OPP_TOLERANCE / 100;
volt_old = regulator_get_voltage(mpu_reg);
}
dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
old_freq / 1000, volt_old ? volt_old / 1000 : -1,
new_freq / 1000, volt ? volt / 1000 : -1);
/* scaling up? scale voltage before frequency */
if (mpu_reg && (new_freq > old_freq)) {
r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
__func__);
return r;
}
}
ret = clk_set_rate(policy->clk, new_freq * 1000);
/* scaling down? scale voltage after frequency */
if (mpu_reg && (new_freq < old_freq)) {
r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
__func__);
clk_set_rate(policy->clk, old_freq * 1000);
return r;
}
}
return ret;
}
static inline void freq_table_free(void)
{
if (atomic_dec_and_test(&freq_table_users))
dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
}
static int omap_cpu_init(struct cpufreq_policy *policy)
{
int result;
policy->clk = clk_get(NULL, "cpufreq_ck");
if (IS_ERR(policy->clk))
return PTR_ERR(policy->clk);
if (!freq_table) {
result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
if (result) {
dev_err(mpu_dev,
"%s: cpu%d: failed creating freq table[%d]\n",
__func__, policy->cpu, result);
goto fail;
}
}
atomic_inc_return(&freq_table_users);
/* FIXME: what's the actual transition time? */
result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
if (!result)
return 0;
freq_table_free();
fail:
clk_put(policy->clk);
return result;
}
static int omap_cpu_exit(struct cpufreq_policy *policy)
{
freq_table_free();
clk_put(policy->clk);
return 0;
}
static struct cpufreq_driver omap_driver = {
.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = omap_target,
.get = cpufreq_generic_get,
.init = omap_cpu_init,
.exit = omap_cpu_exit,
.name = "omap",
.attr = cpufreq_generic_attr,
};
static int omap_cpufreq_probe(struct platform_device *pdev)
{
mpu_dev = get_cpu_device(0);
if (!mpu_dev) {
pr_warn("%s: unable to get the MPU device\n", __func__);
return -EINVAL;
}
mpu_reg = regulator_get(mpu_dev, "vcc");
if (IS_ERR(mpu_reg)) {
pr_warn("%s: unable to get MPU regulator\n", __func__);
mpu_reg = NULL;
} else {
/*
* Ensure physical regulator is present.
* (e.g. could be dummy regulator.)
*/
if (regulator_get_voltage(mpu_reg) < 0) {
pr_warn("%s: physical regulator not present for MPU\n",
__func__);
regulator_put(mpu_reg);
mpu_reg = NULL;
}
}
return cpufreq_register_driver(&omap_driver);
}
static int omap_cpufreq_remove(struct platform_device *pdev)
{
return cpufreq_unregister_driver(&omap_driver);
}
static struct platform_driver omap_cpufreq_platdrv = {
.driver = {
.name = "omap-cpufreq",
},
.probe = omap_cpufreq_probe,
.remove = omap_cpufreq_remove,
};
module_platform_driver(omap_cpufreq_platdrv);
MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
MODULE_LICENSE("GPL");
|
